The healing mechanism of a small wound which had been made on the posterior surface of the rabbit cornea was studied by electron microscopy. Due to the curling characteristic of the cut edge of Descemet's membrane, a tissue defect measuring about 200 micron m in width was formed. Endothelial cells in the adjacent area of the wound rapidly slid over the curled Descemet's membrane and then filled up the tissue defect. The cells facing the anterior chamber became the covering endothelium, but many cells in the wound defect transformed into fibroblast-like cells and eventually decreased in number.